I think there's a fair problem here in that a chunk of forum members won't actually remember when conductors were "every day" to really experience what it was like in comparison. Yes, there were Routemasters in London (which I just about remember using... maybe once... in normal service), but that's a small subset of use compared to other cities, or even rural areas. As such, it's hard to make comparisons as to what has actually changed, versus what we perceive has changed, or personal hobbyhorses based on an equally small set of experiences. (Insert my usual statement about my past German town's bus services which connected perfectly well with each other but failed miserably to connect with any rail service, or inter-urban bus, whatsoever, nor was the bus station near the train station, nor was it in either of the next biggest towns North, South or East...)
I don't doubt there are some improvements that could be made, but ultimately, they are likely to cost large amounts for minimal gain, compared to other traffic flow issues. Like the recent changes to road layout on my local bus, which now means buses and other large vehicles can no longer pass each other "mobile" at certain spots. Barely an inch was added to pavement widths, but trees were planted, and at one point, a bus stop box was painted half on a speed hump). We also have 5-way traffic lights for the first three weeks of summer: delays are averaging anywhere between barely any and 9 minutes per trip, with up to 30 minute delays at peaks (for a 25 minute journey). Today, a further set of two-way traffic lights has sprung up a matter of minutes along the route. One of the "local" (i.e. single track ratrun) diversionary routes is due to be closed next week. Lost time through boarding (including from ENCTS passholders not having them ready) is a rounding error compared to those other factors!